如何将STDIN内容转换为数组? [英] How to convert STDIN contents to an array?

问题描述

我有一个具有以下内容的文件输入:

I've got a file INPUT that has the following contents:

123\n
456\n
789

我想像这样运行我的脚本:script.rb< INPUT并使其将INPUT文件的内容转换为数组，并在换行符上进行拆分.所以，我会有类似myArray = [123,456,789]的信息.这是我尝试做的，但运气不佳:

I want to run my script like so: script.rb < INPUT and have it convert the contents of the INPUT file to an array, splitting on the new line character. So, I'd having something like myArray = [123,456,789]. Here's what I've tried to do and am not having much luck:

myArray = STDIN.to_s
myArray.split(/\n/)
puts field.size

我希望它能打印3，但我要打印15.我真的很困惑.有指针吗?

I'm expecting this to print 3, but I'm getting 15. I'm really confused here. Any pointers?

推荐答案

您想要的

myArray = $stdin.readlines

这将把所有$ stdin都放入一个数组，每行输入只有一个数组项.

That'll get all of $stdin into an array with one array entry per line of input.

请注意，对于大型输入文件，这效率极低(在内存方面)，因此，使用以下类似的方法会更好:

Note that this is spectacularly inefficient (memory wise) with large input files, so you're far better off using something like:

$stdin.each_line do |l|
  ...
end

代替

a = $stdin.readlines
a.each do |l|
  ...
end

因为前者并没有为所有事情分配内存.尝试以第二种方式处理一个数千兆字节的日志文件，以查看您的系统的交换性能如何……< grin>

Because the former doesn't allocate memory for everything up-front. Try processing a multi-gigabyte log file the second way to see just how good your system's swap performance is... <grin>

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